why would good faith arguments between anarchists be any different than between others? if someone seems to be in good faith with you, then you act in good faith towards them (and err as much as possible on the side of generosity and humor).
anarchists are just as capable of being facile jackasses in an argument as anyone else is, as well as (perhaps unwitting) perpetrators of sloppy thinking.

The problem is that 'good faith' means different things to different people. I practice good faith in different ways with different people as well. For example, I have non-anarchist friends who consider themselves nihilists and I can say almost anything to them, share my adventures on the toilet, my sexual discomforts, and equally, talk about the weather. In good faith we call each other on shit, fight with each other brutally, and yet, in the end, we share--I feel--a relationship built on good faith. What we share is a respect for the tolerance of each others perversities but on the condition that we recognize when we've gone too far. I can say that these are my best friends. Zizek, echoing Bataille in many ways, says that this is the foundation of friendship and dialog. I happen to agree with him.

Saint_Schmidt, yes, in face to face relationships i agree with what you say. and i would say IRL good faith is practiced more.
the question here, though, seems to refer to internet argument, particularly in sectarian and infighting situations. i don't know about you but most of the argument i see is filtered through this medium and it is rife with bad faith. mis-stating and misrepresenting positions, straw man arguments and ad hominem are the usual modes. very few of the regular poster on various sites i frequent seem to practice good faith argument, most seem only to want to score points with the game veiled. with that in mind, would you have a different take on the question? maybe the interwebs are a lost cause. i think so much of the time, yet i keep coming back.

dot, see my comment above to S_S.
i would add here, who starts the good faith? you said if someone acts in GF with you, then act in GF with them. in first encounters who acts in GF first? it looks like a prisoner's dilemma in a way, maybe. not that that would preclude acting in GF, but would color things. eh, perhaps i spend too much time in the world.

i also said, err on the side of generosity and humor, which was addressing the question of interactions with new people. but actually, i tend to think that acting in good faith is usually the best thing to do, in person and online, because i am the one who gets the most out of my own good-faith-acting. if i am engaging in a point that is interesting to me, why should i be bothered by the intentions of other people? if i am writing online, then how much am i writing for the person who stimulated me, and how much for the others who will read the interaction?
being online gives us at least the illusion of a constant third-party, and using/benefiting from that perspective is one of the main points of the process.

i am sorry to say that in my experience, real life face-to-face interactions are just as wrought with what you are calling "bad faith" as anything i see online. people that have dogmatic attachment to their ideas (folks i would call "ideological") cannot seem to discuss those ideas in good faith, because it would open them up to other, potentially contrasting ideas. or, open them up to being "wrong". and to me, it is the "right vs wrong" mentality that virtually defines "bad faith" argument/debate.

so i guess the key to "good faith" discussion is having it with someone who is not dogmatic. (where dogma often masks or compliments ignorance, ulterior motives, coercion, etc).